xref: /netbsd-src/usr.bin/fmt/buffer.h (revision e5548b402ae4c44fb816de42c7bba9581ce23ef5)
1 /*	$NetBSD: buffer.h,v 1.1 2005/12/15 21:32:00 christos Exp $	*/
2 
3 /*-
4  * Copyright (c) 2005 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Christos Zoulas.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *        This product includes software developed by the NetBSD
21  *        Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 #include <stddef.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <err.h>
43 
44 struct buffer {
45 	char *ptr;
46 	char *bptr;
47 	char *eptr;
48 };
49 
50 static void
51 buf_init(struct buffer *buf)
52 {
53 	buf->ptr = buf->bptr = malloc(BUFSIZ);
54 	if (buf->ptr == NULL)
55 		err(1, "Cannot allocate buffer");
56 	buf->eptr = buf->ptr + BUFSIZ;
57 }
58 
59 static void
60 buf_end(struct buffer *buf)
61 {
62 	free(buf->bptr);
63 }
64 
65 static void
66 buf_grow(struct buffer *buf, size_t minsize)
67 {
68 	ptrdiff_t diff;
69 	size_t len = (buf->eptr - buf->bptr) +
70 	    minsize > BUFSIZ ? minsize : BUFSIZ;
71 	char *nptr = realloc(buf->bptr, len);
72 
73 	if (nptr == NULL)
74 		err(1, "Cannot grow buffer");
75 
76 	if (nptr == buf->bptr)
77 		return;
78 
79 	diff = nptr - buf->bptr;
80 	buf->bptr += diff;
81 	buf->eptr = buf->bptr + len;
82 	buf->ptr += diff;
83 }
84 
85 static __inline void
86 buf_putc(struct buffer *buf, char c)
87 {
88 	if (buf->ptr >= buf->eptr)
89 		buf_grow(buf, 1);
90 	*buf->ptr++ = c;
91 }
92 
93 static __inline void
94 buf_reset(struct buffer *buf)
95 {
96 	buf->ptr = buf->bptr;
97 }
98 
99 static __inline char
100 buf_unputc(struct buffer *buf)
101 {
102 	return buf->ptr > buf->bptr ? *--buf->ptr : '\0';
103 }
104